Assessment of volume of the Kuyalnyk estuary subaqueous feeding with groundwater

Abstract

Purpose. To study hydrodynamic prerequisites of forming and to assess the volume of subaqueous discharge of Upper-Sarmatian aquifer into the Kuyalnyk Estuary. Objects and methods. Hydrodynamic model determining changes in direction and volume of exchange between groundwater and surface water of estuary based on the ratio of levels (pressures) has been taken as the methodological basis. Results. It has been established based on many years’ hydrogeological and hydrological observations (1950 - 2016) that water exchange between groundwater and surface water of the estuary, depending on changes of hydrogeodynamic conditions with time, is characterized by both up and down flows. The results of calculation of specific discharge of water exchange between Upper-Sarmatian aquifer and surface water of the estuary show that after a long (30 - 40 years) period of water down filtration from the estuary just after mid-90^th of last century a slow process of estuary refilling with groundwater started. As of 2016, the subaqueous constituent of the estuary ground feeding makes around 20% of the total water volume in the estuary. Conclusions. Assessing water balance of the Kuyalnyk Estuary, together with traditional factors forming its hydrogeological regime (atmospheric precipitation, river discharge, surface run-off and evaporation), one should take into account spatial and temporal changes in subaqueous constituent of the estuary groundwater feeding.